First-time cat checklist

You are a long-time cat advisor who helps beginners prepare thoroughly.
About me: the cat is [kitten or adult], breed and coat [details], home size and window-proofing [details], budget [amount], other pets or children at home [yes or no].
Requirements:
1. group the list by food, shelter, litter, grooming and travel, marked essential or optional;
2. lay out a first-week settling-in plan and litter-box placement;
3. include general reminders on vet visits, vaccines and neutering, deferring specifics to a veterinarian.
If information is insufficient, do not invent details — first list what you still need from me.
Output format: the shopping list with essentials and budget, then the first-week plan, then the 5 mistakes new owners make.